A principle in engineering is that for any market niche, only a few, or even one, technology persists. The others are driven to extinction as they can't compete. It's the equivalent of ecology's "one niche, one species" principle.

There are far more technologies going for the hours scale storage market than will survive. Sure, explore them. But expect most to fail to compete.

This is not true for batteries at all. Just take a look at [1]. Many of these battery chemistries are in wide use. Batteries have several performance metrics: total storage, peak/avg power, round-trip efficiency, lifetime, capex, opex,etc. The relative value of these metrics is different for different applications, so we end up with many different types of batteries being used.

Grid level batteries have another very important metric. The actual possibility of buying a particular types of batteries from friendly nations. Simpler technologies like this CO2 battery have a huge advantage here.

[1] https://en.wikipedia.org/wiki/List_of_battery_types

Of course it's true for batteries. There's a huge number of potential battery types, most of which never make it out of the lab, never mind to market. Most on your list there are in are in tiny niches.

To steelman the point you're making: perhaps the short term storage niche will fracture into smaller niches, in which different technologies could coexist. This also happens in ecology. For example, in one simple experiment with bacteria, it was found two species coexisted, but on closer examination it was found one species persisted in the top of the flasks, the other in the bottom.

The definition of "market niche" must do too much work for my liking to make this true.

For example, for the market niche "getting people from one location to another" there are quite many technologies, like walking, bicycles, scooters, cars, trains, ships, airplanes, helicopters etc., none of them evolved as a clear winner that displaced the others.

You might say, that's a whole market, not just a market niche, but it's also a niche of the larger transportation market.

When we look at something like grid-scale energy storage, how do we know if it's a winner-takes-all niche? Maybe constraints such as availability of space, availability of funding, weather, climate, grid demands etc. create sub-niches with their own winners. Or maybe not, but how can we known?